Improvement in pavements



UNITED STATES WILLIAM H. JONES, OF ROCHESTER, NEW YORK.

IMPROVEMENT IN PAVEMENTS.

Specification forming part of Letters Patent No. 169.005, dated October 19, 1875; application filed May 26, 1875.

To all whom it may concern:

Be it known that I, WILLIAM H. JONES, of the city of Rochester, in the county of Monroe and State of New York, have invented a certain new and useful Improvement in Streetnarily prepared, is either too friable or too soft, in the one case cracking and breaking up and allowingwater to enter, and in the other yielding and rolling under tread and not furnishing a solid surface; second, in an imperfect construction of the substructure, be-

ing so porous and open that the cement strikes through, thus requiring a very heavy body, which is liable to crack and admit water, which, when frozen, heaves the pavement, thereby destroying it.

To obviate these difficulties my invention consists in forming the surface of the pavement of coal-tar distilled in a closed vessel till twenty-five per cent. of its body is removed, leaving the residuum in proper condition to be applied in a thin body, retaining all its natural elasticity and adhesion without making it brittle also, in the construction of the road-bed as hereinafter described, whereby a dam? or out-ofl' layer is interposed between the cement layer and substructure, by which means the cement is prevented from penetrating to any considerable depth, but is formed in a thin body, which is tough, elastic, and impermeable to water.

In the construction of my pavement I excavate the road-bed as usual to proper depth say, about eighteen inches, more or less. I fill this excavation about ten inches deep with small stone or coarse stone chips, and prop erly break it down with sledges, filling the interstices with small stone chips to produce a level surface. This forms the foundation a. I next fill in on top of this a layer of coarse macadain or small broken stone, which, when thoroughly rolled, is about five inches in depth, and rests about three inches below the grade of the street. This forms the coarse filling b above the foundation. I next fill in a layer of fine stone-dust or sand, one inch, more or less, in depth, or enough to thoroughlycover the stone, which forms a dam or cutoff layer, 0, to prevent the passage of the coaltar through to the stone. I next fillin alayer oftine m acadam about three inches deep, which is thoroughly rolled to make it solid and com-' pact and present a"perfeotly smooth surface. This layer, when thoroughly rolled, lills up to the grade of the street. The material forming this layer should be fine, and the rolling action should be thorough in order to make it as hard and solid as possible. This layer forms the body (1 for receiving the cement.

To prepare the cement, I take ordinary coaltar and place it in a closed retort or still, and apply heat beneath in the usual manner for distilling liquids. The distilling action is. carried forward till twenty-five per cent, or thereabout, of the body of the coar-tar is removed, the residuum forming the cement which is, used. The portion which is distilled off is the volatile matter, which, in quantity, is only a detriment to this use. I

The residuum is drawn off from the still, and, in a hot state, is then poured in three successive spreading-s from buckets upon the road-bed already prepared, and is thoroughly stirred to level and even it. A comparatively thin layer only is required, just sufficient to cover and fill the surface, much thinner than in ordinary eementpavements, and the thinness of the layer is one merit, since it is more elastic, and consequently much more endurin g, than a thick friable layer, as well as much cheaper. When the cement is laid, sand or fine stone-dust is spread over it and rolled in while the cement is hot.

One important advantage in the construction of this pavement is the preparation of the cement. Having been a street-contractor and manufacturer of rooting for many years, I have experimented, largely with coal-tar, and, as ordinarily applied, it is very imperfect. If the volatile elements of the tar, or

PATENT QFFIGE.

any considerable portionthereof; are left in the cementgrit is soft, sticky, and lacks-in substance. If they are burned out by setting fire to the mass, or by boiling in kettles in the open air, as has heretofore been done, the residuum will be thick, turgid,'and, whenapplied, exceedingly brittle. This is owing partial-ly to too much loss of the lighter qualities, which necessarily pass off, but in a great degree to the burning of the material, forming thereby a powdery sediment, that is dry andlacks in adhesion. When applied upon a pavement, such a cement will soon crack and break, and thereby admit water.

By distilling the coal-tar in a closed still, I

remove the volatile matters without burning. thematerial, and without the loss of the elastie and adhesive qualities necessary for a cement of this kind. I do not claim broadly,

however, distilling. coal-tar, as this has before beendone. But in the course of my experiments I have found it necessary in tlie'production of a perfect cement-for street-pavements to remove, by distillatioma specific quantity of the lighter elements, which= is twenty-five per cent., or approximating; that from the use of the solidlayer ofisand orfine stone-dust interposedbetweeuthe cement and the substructure, the same forminga-dam -or cut-oit'to the cement,.so that. it cannot pass through into the stone. Sand or stonedust, as is well known, is a perfect barrier to the passage of coaltar. 'By this means I cover only the topof the road'bed with cement and prevent its passage to the stone;

whereas, in all other cementpavements with which I amacquainted, the cement is-allowed to penetrate the stone, thereby necessarily requiring a heavy body and rendering it so thick that it will crack and break. In my invention the cement simply penetrates the upper layer of 'macadam, but does not pass the sand. When properly prepared the street is watcr-proof, and its arched form in crosssection will throw the water to the gutters.

"I am aware that sand has before been placed on the stone as a filling for the same; but not,

so far as I am aware, for the purpose of form; ing a cut-off or dam to the cement.

A pavement, made in the manner above described, will stand. the test. of both heat and cold, as I" have demonstrated impractical use, the thin coating. of cement prepared by the distilling being so elastic asto prevent breakage and' efi'ectually shut-ting out water and alsomade atmuch less expense.

Having thus described myinvention ldo not claim broadlya layer of saud placed upon thefoundation of stone; but.

Wh'atTI claim as new is-- 1. A cem ent covering fora street-pavement,

consisting of the residuum ofcoal-tardistilled in a close vessel till twenty-five per cent.,=or approximating that amount, of its bulk is re moved, as herein described. a

I 2. A street-pavement, consisting of a-foun dation layer of smallstone or coarse stone chips, abody-layer of coarse macadam, a dam or cut-oft layer of sand or fine stone-dust, a surface'layer of fine macadam,and a cement coveringof coal-tar withtwenty-five per cent.

of its bulk removed by distilling: inaclosed vessel, the whole combiued, as described, so that the cementin a thin body permeates the upper layer, but is prevented from passing through to the substructure by the damior cut ofl' layer of sand, as set forth.

In witness whereof I have hereunto signed my nameinithe presence of two subscribing witnesses.

Witnesses:

R. F. Oseoon, J. .N. ()oLEa WILLIAM! H. JONES. 

